Tire pressure monitoring systems are known in the art. Such known systems include a plurality of sensor assemblies, each sensor assembly mounted to an associated vehicle wheel inside of the associated tire and powered by a long-life battery. The sensor assembly includes a pressure sensor and a temperature sensor that monitors the tire pressure and temperature, respectively. When the tire pressure is below a threshold, a transmitter circuit of the sensor assembly transmits an RF signal to a vehicle-based receiver indicating a low-pressure condition. The vehicle-based receiver, upon receiving a low-pressure indication from a sensor assembly, activates an indicator within the passenger compartment to warn the driver. Tire pressure and temperature sensors also transmit pressure and temperature information periodically.
In a sensor system that includes four sensor assemblies for a vehicle, each sensor will have an associated identification code to distinguish itself from the other sensor assemblies of the vehicle. As part of transmission of a low tire pressure signal, each sensor assembly, upon detecting a low-pressure condition, transmits its identification code along with an indication of the low-pressure condition. Assuming the vehicle-based receiver is preprogrammed to associate a particular identification code with a particular tire location, the receiver can control a low-pressure indicator or display within the vehicle compartment to indicate the tire location having the low-pressure condition.
Antilock brake systems often have wheel speed sensors electrically connected to a vehicle-based controller through a hard-wired connection. Such systems may include a wheel speed sensor mounted near a toothed plate, the toothed plate being connected to an associated vehicle wheel to rotate as the wheel rotates. The controller monitors vehicle wheel rotation by monitoring electrical pulses from each wheel speed sensor. The antilock braking system provides slip control of the wheels via control of a hydraulic modulator by the controller during a braking condition to prevent wheel lock-up.